Coil device

ABSTRACT

A coil device of solenoid type includes a coil portion having a bobbin and a conductive wire wound around the bobbin, a housing for accommodating the coil portion, and at least one fastener for fastening the bobbin and the housing. The conductive wire includes a plurality of extending portions extending along a wound wire direction on the bobbin and having gaps in a winding axis direction. The fastener is provided between the plurality of extending portions and is obliquely disposed with respect to a plane orthogonal to the winding axis direction.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of InternationalApplication No. PCT/JP/2015/061154, filed Apr. 9, 2015, which claimspriority to Japanese Patent Application No. 2014-105907, filed on May22, 2014. The contents of these applications are incorporated herein byreference in their entirety.

TECHNICAL FIELD

The present disclosure relates to a coil device.

BACKGROUND ART

A wireless power transfer system includes a power transmission coildevice and a power reception coil device, and implements wireless powertransfer using electromagnetic induction, magnetic resonance, etc.between coils. Each of the coil devices has a coil and ferrite therein.The coil device is surrounded by a housing. For example, the housingincludes a protective cover and an aluminum plate. For example, thewireless power transfer system is applied to a power feeding system ofan electric vehicle. In this case, the power reception coil device isinstalled in the vehicle.

Technologies disclosed in Patent Literatures 1, 2, and 3 are known. Inan apparatus disclosed in Patent Literature 1, an in-vehicle transducercorresponding to a power reception coil device is installed in a vehicle(chassis). Alternatively, the in-vehicle transducer is installed toprotrude downward on a lower surface of a vehicle body. In an apparatusdisclosed in Patent Literature 2, a bobbin that supports a secondaryself-resonant coil corresponding to a power reception coil is attachedto a vehicle by a fixing member connected to a flange portion thereof.

In an apparatus disclosed in Patent Literature 3, an aluminum substrateof a power reception unit is fixed to a lower portion of a moving bodyby a non-magnetic bolt through a bolt hole. An aluminum substrate of apower feeding unit (power transmitter) is fixed to a road surface, etc.by a non-magnetic bolt through a bolt hole. A protective cover made ofpolycarbonate is fixed to the substrate by a non-magnetic bolt through abolt hole. A spacer is provided between the protective cover and aninsulating plate, and strength of the protective cover is increased bythe spacer.

CITATION LIST Patent Literature

Patent Literature 1: Japanese Unexamined Patent Publication No.2013-153132

Patent Literature 2: Japanese Unexamined Patent Publication No.2010-87353

Patent Literature 3: Japanese Unexamined Patent Publication No.2008-120239

SUMMARY Technical Problem

In a solenoid coil disclosed in Patent Literature 1, a bobbin aroundwhich a conductive wire is wound (a ferrite housing portion in theapparatus of Patent Literature 1) is disposed to extend in a flat plateshape between a protective cover and an aluminum plate. A plurality ofslot-shaped grooves is formed in the bobbin, and the conductive wire isdisposed in the grooves. In this configuration, the conductive wirewound around the bobbin has a plurality of parallel linear portions oneach of a surface side and a rear surface side of the bobbin. Therefore,the conductive wire is present over the entire area of the bobbindisposed between the protective cover and the aluminum plate.

A spacer disclosed in Patent Literature 3 is known to be provided toincrease strength of a housing. However, there is difficulty in applyingthe spacer to a solenoid coil in which a conductive wire is present overthe entire area of a bobbin. Increasing strength of the housing is anissue in a coil device that employs the solenoid coil.

An object of the present disclosure is to provide a coil device ofsolenoid type capable of increasing strength of a housing.

Solution to Problem

A coil device according to an aspect of the present disclosure is a coildevice of solenoid type including a coil portion having a bobbin and aconductive wire wound around the bobbin, a housing for accommodating thecoil portion, and at least one fastener for fastening the bobbin and thehousing, wherein the conductive wire includes a plurality of extendingportions extending along a wound wire direction on the bobbin and havinggaps in a winding axis direction, and the fastener is provided betweenthe plurality of extending portions, and is obliquely disposed withrespect to a plane orthogonal to the winding axis direction.

According to this coil device, the housing accommodates the coil portionthat includes the bobbin. The at least one fastener is provided betweenthe plurality of extending portions extending in the wound wiredirection on the bobbin. The bobbin and the housing are fastened by thefastener. Since the fastener is obliquely disposed with respect to theplane orthogonal to the winding axis direction, it is easy to avoidinterfering in the extending portions of the conductive wire by thefastener. In other words, a degree of freedom is increased when thefastener is provided. Therefore, strength of the housing may beincreased in the coil device of solenoid type.

In some embodiments, the coil portion further includes a magnetic memberdisposed inside the bobbin. In this case, power efficiency is increased.

In some embodiments, the housing includes a first housing member facinga first surface of the coil portion having a flat plate shape, and asecond housing member fixed to the first housing member to face a secondsurface on an opposite side from the first surface. In this case,strength of the housing may be increased by fastening the bobbin and atleast one of the first housing member and the second housing member bythe fastener.

In some embodiments, the bobbin includes a first winding plate disposedbetween the first housing member and the magnetic member, and a secondwinding plate disposed between the second housing member and themagnetic member, and the fastener penetrates through the magnetic memberand fastens the first winding plate and the second winding plate. Inthis case, the magnetic member is provided between the first housingmember and the second housing member. The fastener penetrates throughthe magnetic member, and the first winding plate and the second windingplate are fastened, and thus the housing is more strongly fixed to thebobbin.

In some embodiments, a hole portion is provided in the magnetic member,one of the first winding plate and the second winding plate includes aprotrusion protruding to an inside of the hole portion, and the fastenerpenetrates through the protrusion to fasten the first winding plate andthe second winding plate. In this case, the fastener penetrates throughthe protrusion disposed inside the hole portion of the magnetic memberto fasten the first winding plate and the second winding plate. Thefirst winding plate and the second winding plate are more stronglyfastened. The magnetic member is sandwiched between and held by thefirst winding plate and the second winding plate. The magnetic membermay be fragile. However, according to the above configuration, strengthof the magnetic member may be increased.

In some embodiments, the fastener includes a flange portion contactingthe first winding plate from a side of the first housing member, and thefirst housing member is supported by the coil portion through the flangeportion. In this case, since the first housing member is supported bythe coil portion, the first housing member may be prevented from beingbent around the fastener.

In some embodiments, the fastener penetrates through the housing.Fastening using the fastener is performed from the outside of thehousing, and thus the fastener may be reliably and easily provided.

In some embodiments, the fastener includes a first combined memberintegrally provided in the first housing member to protrude toward thesecond housing member, and a second combined member integrally providedin the second housing member to protrude toward the first housingmember, and at least one of the first combined member and the secondcombined member is disposed inside the coil portion, and the firstcombined member and the second combined member are combined together. Inthis case, the fastener does not penetrate through the housing, and thusa seal around the fastener is not needed.

In some embodiments, the coil portion includes an equal portion in whicha gap between extending portions adjacent to each other in the windingaxis direction is equal to a gap between other extending portions, andthe fastener is provided in the equal portion. In this case, a pitch ofthe conductive wire in the equal portion of the coil portion is equal toa pitch in another portion, and thus influence on a magnetic field maybe made as small as possible. The fastener is obliquely disposed withrespect to the plane orthogonal to the winding axis direction. Thus,even when the fastener is provided in the equal portion, interference inthe conductive wire may be easily avoided.

In some embodiments, the fastener is provided in a central region of thebobbin in the wound wire direction and the winding axis direction. Inthis case, strength of the housing is increased at a positioncorresponding to the central region of the bobbin. The housing isrelatively easily bent at the position corresponding to the centralregion of the bobbin. Therefore, strength of the housing is furtherimproved.

In some embodiments, the fastener is provided in a central region of thehousing in the wound wire direction and the winding axis direction. Inthis case, strength of the housing is increased at a positioncorresponding to the central region of the housing. The housing isrelatively easily bent in the central region. Therefore, strength of thehousing is further improved.

In some embodiments, the fastener is provided in a region in which adecrease in power efficiency due to provision of the fastener is lessthan or equal to 0.1%. In this case, an influence on power efficiency bythe fastener may be made as small as possible.

In some embodiments, the fastener is provided in a region in which amagnetic flux density in the coil portion is lower than a magnetic fluxdensity in another region. In this case, an influence on a magnetic fluxby the fastener may be made as small as possible.

In some embodiments, the at least one fastener includes a plurality offasteners, and the plurality of fasteners are arranged along the windingaxis direction.

In some embodiments, the at least one fastener includes a plurality offasteners, and the plurality of fasteners are arranged along the woundwire direction.

Effects

According to some embodiments of the present disclosure, strength of ahousing may be increased in a coil device of solenoid type.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating an application example of a coil deviceaccording to an embodiment of the present disclosure.

FIG. 2 is a perspective view illustrating the coil device according tothe embodiment of the present disclosure.

FIG. 3A is a cross-sectional view schematically illustrating a portionin which a fastener is provided, and FIG. 3B is a diagram describing apositional relationship of a conductive wire of FIG. 3A.

FIG. 4 is a cross-sectional view illustrating a portion around thefastener of FIG. 2.

FIG. 5 is a plan view illustrating central regions of a housing and abobbin.

FIG. 6A is a plan view illustrating an installation position of thefastener when a magnetic flux density or power efficiency is considered,and FIG. 6B is a plan view illustrating an installation position of thefastener when strength is considered.

FIG. 7 is a plan view illustrating a region in which a regionillustrated in FIG. 6A overlaps a region illustrated in FIG. 6B.

FIG. 8 is a cross-sectional view schematically illustrating a portion inwhich a fastener is provided in another embodiment.

FIG. 9 is a cross-sectional view schematically illustrating a portion inwhich a fastener is provided in another embodiment.

FIG. 10 is a cross-sectional view schematically illustrating a portionin which a fastener is provided in another embodiment.

FIG. 11 is a cross-sectional view schematically illustrating a portionin which a fastener is provided in another embodiment.

FIG. 12 is a cross-sectional view schematically illustrating a keystructure of a housing in another embodiment.

FIG. 13A is a plan view illustrating a mode in which two fasteners arearranged in a winding axis direction, and FIG. 13B is a plan viewillustrating a mode in which two fasteners are arranged in a wound wiredirection.

FIG. 14 is a cross-sectional view describing a case in which a fasteneris provided in a conventional solenoid coil.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present disclosure will be describedwith reference to drawings. The same reference numeral will be appliedto the same component in description of the drawings, and repeateddescription will be omitted.

A wireless power transfer system 1 to which a coil device of the presentembodiment is applied will be described with reference to FIG. 1. Thewireless power transfer system 1 is a system for feeding power from apower transmitter 2 to a power receiver 3. For example, the powertransmitter 2 and the power receiver 3 are separated from each other ina vertical direction. For example, the power transmitter 2 is installedin a parking lot, etc. For example, the power receiver 3 is installed inan electric vehicle EV. The wireless power transfer system 1 isconfigured to feed power to the EV arriving at the parking lot, etc.using a magnetic resonance scheme, an electromagnetic induction scheme,etc.

The power transmitter 2 includes a power transmission coil device 4 forwireless power transfer provided to protrude upward from a road surfaceof the parking lot, etc. For example, the power transmission coil device4 has a shape of a flat rectangular parallelepiped or frustum. The powertransmitter 2 generates desired AC power from a DC power source or an ACpower source to send the generated AC power to the power receiver 3, andfurther includes a controller, an inverter, etc. (not illustrated). Forexample, the power receiver 3 includes a power reception coil device 5for wireless power transfer attached to a bottom surface of a vehiclebody (chassis, etc.) of an EV to face the power transmission coil device4. For example, the power reception coil device 5 has a shape of a flatrectangular parallelepiped or frustum. The power receiver 3 receivespower from the power transmitter 2 to feed power to a load (e.g., abattery), and further includes a controller, a rectifier, etc. (notillustrated). Hereinafter, the power transmission coil device 4 and thepower reception coil device 5 will be referred to as a coil device 4 anda coil device 5, respectively.

The coil device 5 will be described with reference to FIG. 1 and FIG. 2.The coil device 5 generates an induced current when a magnetic fluxgenerated by the power transmission coil device 4 interlinks with thecoil device 5. The coil device 5 corresponds to a solenoid type. Thecoil device 5 includes a flat plate-shaped coil portion C that generatesan induced current and a housing 10 that accommodates the coil portionC.

For example, the housing 10, which has a shape of a flat rectangularparallelepiped, includes a base (second housing member) 12 and aprotective cover (first housing member) 11 that forms an accommodationspace between the protective cover 11 and the base 12 (see FIG. 3A andFIG. 3B). The protective cover 11 faces a surface (first surface) C1 ofthe coil portion C. The base 12 faces a rear surface (second surface onthe opposite side from the first surface) C2 of the coil portion C. Whenthe coil device 5 is installed in the EV, for example, the base 12 isfixed to the vehicle body side. The protective cover 11 faces the coildevice 4. That is, the base 12 is disposed above the coil portion C, andthe protective cover 11 is disposed below the coil portion C while thecoil device 5 is installed in the EV. For example, the base 12 and theprotective cover 11 are made of resin. Alternatively, the base 12, whichdoes not face the coil device 4, may be formed using a non-magnetic orconductive material (e.g., aluminum).

The base 12 is a portion fixed to the vehicle body of the EV. Forexample, the base 12 is fixed to the vehicle body by four screw members15 at four corner portions. The base 12, which has a rectangular shape,includes a rectangular-shaped accommodating depression 12 a slightlysmaller than an external form thereof. The coil portion C isaccommodated in the accommodating depression 12 a, and is fixed to thebase 12 by a screw member such as a screw. An insulation sheet may beinserted between the coil portion C and the base 12.

For example, the protective cover 11, which has a rectangular shape, isfixed to the base 12 by four screw members 14 through four screw holes13 at edges of the base 12. A gap G (see FIG. 4) is formed between theprotective cover 11 and the coil portion C substantially over the entireregion of the surface C1 of the coil portion C. A fastener 16 describedbelow is provided at a center of the protective cover 11. A seat 11 band a through-hole 11 c for providing the fastener 16 are formed in theprotective cover 11. The gap G extends between the protective cover 11and the coil portion C in a region except for a portion in which thethrough-hole 11 c is formed.

As illustrated in FIG. 2, FIG. 3A and FIG. 3B, the coil portion Cincludes a conductive wire 30 corresponding to a litz wire, and a flatplate-shaped bobbin 20 around which the conductive wire 30 is wound. Thebobbin 20 includes a rectangular-shaped first winding plate (firstwinding plate) 21 disposed on the surface C1 side, and arectangular-shaped second winding plate (second winding plate) 22disposed on the rear surface C2 side. The first winding plate 21 and thesecond winding plate 22 are formed using the same material (e.g., apolyphenylene sulfide resin).

A ferrite plate (magnetic member) 23 is disposed between the firstwinding plate 21 and the second winding plate 22. That is, the ferriteplate 23 is disposed inside the bobbin 20. In plan view, a shape and asize of the ferrite plate 23 are substantially equal to or smaller thanshapes and sizes of the first winding plate 21 and the second windingplate 22. The ferrite plate 23 is sandwiched between and held by thefirst winding plate 21 and the second winding plate 22. The firstwinding plate 21 is disposed between the ferrite plate 23 and theprotective cover 11. The second winding plate 22 is disposed between theferrite plate 23 and the base 12.

The magnetic member is not restricted to the ferrite plate. The magneticmember may be made of another magnetic material (e.g., a silicon steelplate, an amorphous magnetic alloy, and a magnet). In particular, themagnetic member may be made of a soft magnetic material (e.g., ferrite,a silicon steel plate, and an amorphous magnetic alloy) in terms ofimproving power efficiency. In addition, a component disposed inside thebobbin 20 is not restricted to the magnetic member, and may correspondto a reinforcing material that fills a portion or a whole of a cavityinside the bobbin 20 to ensure strength of the coil portion C. Further,the present invention is not limited to a case in which the magneticmember or the reinforcing material is disposed inside the bobbin 20. Thecoil portion C may be an air-core coil in which the inside of the bobbin20 remains as a cavity. Power efficiency refers to a ratio of power at acertain place inside the power receiver 3 to power at a certain placeinside the power transmitter 2. For example, power efficiency refers aratio of power of an output of a rectifier of the power receiver 3 topower of an input of an inverter of the power transmitter 2. Herein, theinverter of the power transmitter 2 generates AC power, which istransmitted from the power transmitter 2 to the power receiver 3, fromDC power (power obtained by rectifying an output from the DC powersource or an output from the AC power source, etc.). The rectifier ofthe power receiver 3 converts AC power from the power transmitter 2 intoDC power (e.g., power input to the battery).

For example, a plurality of groove portions 21 b extending in along-side direction of the coil portion C is formed in the first windingplate 21. The plurality of groove portions 21 b is parallel to eachother, and is formed at equal intervals. A cross-sectional shape of theplurality of groove portions 21 b perpendicular to the long-sidedirection corresponds to a rectangular shape in which one side on theprotective cover 11 side is open. The groove portion 21 b is recessedwith respect to a surface 21 a of the first winding plate 21, and has apredetermined depth.

For example, a plurality of groove portions 22 b extending in thelong-side direction of the coil portion C is formed in the secondwinding plate 22. The plurality of groove portions 22 b is parallel toeach other, and is formed at equal intervals. A cross-sectional shape ofthe plurality of groove portions 22 b perpendicular to the long-sidedirection corresponds to a rectangular shape in which one side on thebase 12 side is open. The groove portion 22 b is recessed with respectto a surface 22 a of the second winding plate 22, and has apredetermined depth.

The first winding plate 21, the ferrite plate 23, and the second windingplate 22 described above are integrated with one another, and are woundwith the conductive wire 30. More specifically, the conductive wire 30is disposed inside the groove portion 21 b and the groove portion 22 b.As illustrated in FIG. 3A and FIG. 3B, in the coil portion C, a positionat which the groove portion 21 b is provided and a position at which thesurface 22 a is provided are different from each other in a short-sidedirection of the coil portion C. In other words, the groove portion 21 band the groove portion 22 b are not aligned in the vertical direction (adirection perpendicular to the surface C1 of the coil portion C, thatis, a plate thickness direction of the first winding plate 21 and thesecond winding plate 22).

According to the above configuration, the conductive wire 30 woundaround the bobbin 20 includes a plurality of surface-side extendingportions 31 extending on the first winding plate 21 and a plurality ofrear surface-side extending portions 32 extending on the second windingplate 22. The long-side direction of the coil portion C is equal to awound wire direction of the conductive wire 30, and the short-sidedirection of the coil portion C is equal to a winding axis direction ofthe conductive wire 30. The wound wire direction and the winding axisdirection are orthogonal to (intersect with) each other. The conductivewire 30 extends in a direction which is inclined with respect to thevertical direction on an end surface of the bobbin 20 in the wound wiredirection. The respective surface-side extending portions 31 and therespective rear surface-side extending portions 32 are not aligned inthe vertical direction. The surface-side extending portions 31 and therear surface-side extending portions 32 are provided in a verticallydiagonal shape (in zigzag) when viewed in the wound wire direction (seeFIG. 3A and FIG. 3B). When the conductive wire 30 is disposed asdescribed above, portions of the conductive wire 30 are separated fromeach other as much as possible, and an insulation distance is ensured inthe coil portion C.

A more detailed description will be given of the surface-side extendingportions 31 and the rear surface-side extending portions 32 withreference to FIG. 3A, FIG. 3B and FIG. 4. The plurality of surface-sideextending portions 31 extending along the wound wire direction havelinear shapes, and are parallel to each other. As described above, theplurality of groove portions 21 b is formed at equal intervals. Asillustrated in FIG. 3B, a distance between centers, that is, a pitch oftwo surface-side extending portions 31 and 31 is a pitch P1. The pitchP1 is uniform in the plurality of surface-side extending portions 31formed on the first winding plate 21. When distances between thesurface-side extending portions 31 are compared, pitches may be used forthe comparison as described above, or gaps between the surface-sideextending portions 31 may be used for the comparison as illustrated inFIG. 4. A gap between the surface-side extending portions 31 and 31,that is, a distance between two inner end surfaces facing each other inthe winding axis direction is a gap D1. The gap D1 is uniform in theplurality of surface-side extending portions 31 formed on the firstwinding plate 21.

The coil portion C includes an equal portion 35 in which a gap D1between surface-side extending portions 31 and 31 adjacent to each otherin the winding axis direction is equal to a gap D1 between othersurface-side extending portions 31 and 31. In the coil portion C, a gapbetween arbitrary surface-side extending portions 31 and 31 adjacent toeach other among the plurality of surface-side extending portions 31 isthe gap D1 which is equal to a gap between other portions. A pluralityof equal portions 35 is formed on the first winding plate 21 of the coilportion C.

The plurality of rear surface-side extending portions 32 extending alongthe wound wire direction have linear shapes, and are parallel to eachother. As described above, the plurality of groove portions 22 b isformed at equal intervals. As illustrated in FIG. 3B, a distance betweencenters, that is, a pitch of two rear surface-side extending portions 32and 32 is a pitch P1. The pitch P1 is uniform in the plurality of rearsurface-side extending portions 32 formed on the second winding plate22. A gap between the rear surface-side extending portions 32 and 32,that is, a distance between two inner end surfaces facing each other inthe winding axis direction is a gap D1. The gap D1 is uniform in theplurality of rear surface-side extending portions 32 formed on thesecond winding plate 22.

The coil portion C includes an equal portion 35 in which a gap D1between rear surface-side extending portions 32 and 32 adjacent to eachother in the winding axis direction is equal to a gap D1 between otherrear surface-side extending portions 32 and 32. In the coil portion C, agap between arbitrary rear surface-side extending portions 32 and 32adjacent to each other among the plurality of rear surface-sideextending portions 32 is the gap D1 which is equal to a gap betweenother portions. A plurality of equal portions 35 is formed on the secondwinding plate 22 of the coil portion C.

As illustrated in FIG. 2 to FIG. 5, the fastener 16 capable ofincreasing strength of the protective cover 11 is provided in the equalportion 35 in which a pitch of the conductive wire 30 is uniform. A holeportion 26 in which the fastener 16 is provided is obliquely formed inthe bobbin 20 of the coil portion C to pass between the surface-sideextending portions 31 and 31 and between the rear surface-side extendingportions 32 and 32. According to this arrangement, interference in theconductive wire 30 by the fastener 16 is avoided.

As illustrated in FIG. 3B, symmetry between the surface-side extendingportions 31 and the rear surface-side extending portion 32 is maintainedin the coil portion C. The rear surface-side extending portion 32 ispositioned at a center of the surface-side extending portions 31 and 31adjacent to each other in the winding axis direction. The surface-sideextending portion 31 is positioned at a center of the rear surface-sideextending portions 32 and 32 adjacent to each other in the winding axisdirection. A relationship of a vertically diagonal shape (a zigzagpositional relationship) is maintained in the coil portion C.

A detailed description will be given of the fastener 16 with referenceto FIG. 4 and FIG. 5. As illustrated in FIG. 5, the fastener 16 isprovided in a first central region A1 which is a central region of thebobbin 20 in the wound wire direction and the winding axis direction. Inother words, the fastener 16 is provided at an intersection point offirst diagonal lines L1 and L1, that is, a central point of the bobbin20.

The fastener 16 may be provided inside the first central region A1, acenter of which corresponds to the intersection point of first diagonallines L1 and L1 of the bobbin 20. The fastener 16 may be provided in asecond central region A2 which is a central region of the housing 10(that is, the protective cover 11 or the base 12) in the wound wiredirection and the winding axis direction. In other words, the fastener16 may be provided at an intersection point of second diagonal lines L2and L2, that is, a central point of the base 12, or may be providedinside the second central region A2, a center of which corresponds tothe intersection point.

As illustrated in FIG. 4, the fastener 16 is obliquely disposed withrespect to a plane perpendicular to the winding axis direction. Theplane perpendicular to the winding axis direction refers to a virtualplane that extends in the wound wire direction and the verticaldirection (that is, the plate thickness direction of the first windingplate 21 and the second winding plate 22). In the present embodiment,the fastener 16 forms an angle with respect to the vertical direction,and forms an acute angle or an obtuse angle (an angle other than 90°)with respect to the winding axis direction. The fastener 16 is disposedin a direction orthogonal to the wound wire direction.

The fastener 16 penetrates through the protective cover 11, the firstwinding plate 21, the ferrite plate 23, and the second winding plate 22.A distal end portion 17 c of the fastener 16 does not penetrate throughthe base 12, and terminates inside the base 12. More specifically, thefastener 16 includes a cylindrical member 18 provided to penetratethrough the first winding plate 21 and the second winding plate 22, acylindrical member 19 provided to penetrate through the protective cover11, and a screw member 17 disposed inside the cylindrical member 18 andthe cylindrical member 19. The cylindrical member 18, the cylindricalmember 19, and the screw member 17 are all made of non-magnetic metal.However, a magnetic material may be used. The cylindrical member 18 isfixed to at least one of the first winding plate 21 and the secondwinding plate 22. The cylindrical member 19 is fixed to the protectivecover 11. The fastener 16 strongly fastens the protective cover 11, thefirst winding plate 21, the ferrite plate 23, the second winding plate22, and the base 12 through the cylindrical members 18 and 19 using thescrew member 17. In addition, when the fastener 16 is made of a materialhaving a thermal conductivity, a portion of heat of the ferrite plate 23heated by wireless power transfer is successively transferred to aprotrusion 22 c and the fastener 16, and is released to the outside froma distal end portion 17 c and the cylindrical member 19. In particular,when the fastener 16 is made of a material having a high thermalconductivity (e.g., metal), heat release effect is increased.

For example, a circular hole portion 23 a is provided at a positioncorresponding to the fastener 16 in the ferrite plate 23. The secondwinding plate 22 includes the protrusion 22 c which has a cylindricalshape and protrudes to the inside of the hole portion 23 a. The holeportion 23 a may be a rectangle. A circular through-hole 22 d thatpenetrates through the second winding plate 22 in a thickness directionis provided at a center of the protrusion 22 c. A through-hole 21 c thatcommunicates with the through-hole 22 d is formed in the first windingplate 21. The protrusion 22 c of the second winding plate 22 is disposedinside the hole portion 23 a of the ferrite plate 23. A surface of theprotrusion 22 c contacts the first winding plate 21.

The cylindrical member 18 includes a flange portion 18 a contacting thefirst winding plate 21 from the protective cover 11 side, a firstcylindrical portion 18 b formed on a distal end side of the flangeportion 18 a and disposed inside the through-hole 21 c of the firstwinding plate 21, and a second cylindrical portion 18 c formed on adistal end side of the first cylindrical portion 18 b and disposedinside the through-hole 22 d of the second winding plate 22. The flangeportion 18 a, which has a disc shape, is provided to be flush with anend surface 11 a of the protective cover 11. The flange portion 18 a,the first cylindrical portion 18 b, and the second cylindrical portion18 c are integrally formed. The first cylindrical portion 18 b and thesecond cylindrical portion 18 c may be formed as separate bodies. Thecylindrical member 19 is disposed inside a through-hole 11 c formed in aseat 11 b, and protrudes from the protective cover 11.

The screw member 17 includes a head portion 17 a disposed on theprotective cover 11 side, a shaft portion 17 b formed on a distal endside of the head portion 17 a to penetrate through the protective cover11, the first winding plate 21, the ferrite plate 23, and the secondwinding plate 22, and a distal end portion 17 c formed on a distal endside of the shaft portion 17 b and screwed to the base 12. The shaftportion 17 b is disposed inside the first cylindrical portion 18 b andthe second cylindrical portion 18 c. A male screw is formed in the shaftportion 17 b and the distal end portion 17 c. The screw member 17penetrates through the first winding plate 21 and the protrusion 22 c ofthe second winding plate 22 to fasten the first winding plate 21, thesecond winding plate 22, and the base 12. A female screw, to which theshaft portion 17 b of the screw member 17 can be screwed, may or may notbe formed in the first cylindrical portion 18 b and the secondcylindrical portion 18 c.

The head portion 17 a protrudes from the end surface 11 a of theprotective cover 11. The seat of the protective cover 11 may be formedto be recessed from the end surface 11 a of the protective cover 11, andthe head portion 17 a may be accommodated in the recessed portion of theseat. When this configuration is employed, the head portion 17 a of thescrew member 17 is positioned on the base 12 side from the end surface11 a of the protective cover 11. Therefore, a position of a lowermostend (that is, a minimum height) of the coil device 5 may be preventedfrom being lowered by the fastener 16. In this way, it is possible toavoid touching an object by the head portion 17 a when the EV is drivenor stopped.

The hole portion 26 of the coil portion C described above (see FIG. 2)includes the through-hole 21 c, the hole portion 23 a, and thethrough-hole 22 d. A seal member is appropriately provided between theprotective cover 11 and the flange portion 18 a. The seat 11 b of theprotective cover 11 protruding to the coil portion C side is fixed tothe flange portion 18 a by applying pressure through the seal member.The protective cover 11 is supported by the coil portion C through theflange portion 18 a.

In the above configuration, the through-hole 11 c of the protectivecover 11, the through-hole 21 c of the first winding plate 21, and thethrough-hole 22 d of the second winding plate 22 are coaxially formed.An axial line thereof obliquely extends with respect to the planeperpendicular to the winding axis direction. The cylindrical member 19and the cylindrical member 18 (the first cylindrical portion 18 b andthe second cylindrical portion 18 c) are coaxially disposed. An axialline thereof is equal to the axial line of the through-hole 11 c, thethrough-hole 21 c, and the through-hole 22 d, and obliquely extends withrespect to the plane perpendicular to the winding axis direction. Theshaft portion 17 b and the distal end portion 17 c of the screw member17 are obliquely disposed with respect to the plane perpendicular to thewinding axis direction. An angle of inclination of the screw member 17may be appropriately changed according to respective positions of thesurface-side extending portions 31 and the rear surface-side extendingportions 32.

The cylindrical member 19, the cylindrical member 18, and the screwmember 17 are obliquely disposed by passing between the surface-sideextending portions 31 and 31 and between the rear surface-side extendingportions 32 and 32. In other words, the fastener 16 is obliquelyprovided to avoid interference in the surface-side extending portions 31and the rear surface-side extending portions 32 in the equal portion 35in which the gap between the surface-side extending portions 31 and 31is equal to a gap between other portions.

When fastening is performed using the fastener 16, the second windingplate 22 in which the through-hole 22 d is provided, the ferrite plate23 in which the hole portion 23 a is provided, and the first windingplate 21 in which the through-hole 21 c is provided are superposed. Forexample, the cylindrical member 18 is fixed to the first winding plate21 and the second winding plate 22, and the first winding plate 21, theferrite plate 23, and the second winding plate 22 are connected to oneanother. Subsequently, the seat 11 b of the protective cover 11 issuperposed on the flange portion 18 a of the cylindrical member 18. Whenthe screw member 17 is screwed in the base 12, the protective cover 11is fastened to the first winding plate 21, the ferrite plate 23, and thesecond winding plate 22. The flange portion 18 a is pressed against thefirst winding plate 21 through the cylindrical member 19. The flangeportion 18 a immobilizes the first winding plate 21 on the base 12 side.In this way, the first winding plate 21 is pressed against the secondwinding plate 22, and the ferrite plate 23 sandwiched between the firstwinding plate 21 and the second winding plate 22 is fixed. Theprotective cover 11 is supported by the base 12 and the coil portion C(bobbin 20) through the flange portion 18 a of the fastener 16.

According to the coil device 5 of the present embodiment, the housing 10is accommodated in the coil portion C that includes the bobbin 20 andthe ferrite plate 23. The fastener 16 is provided between the pluralityof surface-side extending portions 31 and rear surface-side extendingportions 32 extending in the wound wire direction on the bobbin 20. Thebobbin 20 and the housing 10 are fastened by the fastener 16. Since thefastener 16 is obliquely provided with respect to the plane orthogonalto the winding axis direction, it is easy to avoid interfering in thesurface-side extending portions 31 and the rear surface-side extendingportions 32 of the conductive wire 30 by the fastener 16. In otherwords, a degree of freedom is increased when the fastener 16 isprovided. Therefore, strength of the housing 10 is increased in the coildevice 5 of solenoid type.

The housing 10 includes the protective cover 11 and the base 12.Strength of the housing 10 is increased by fastening the bobbin 20 andboth the protective cover 11 and the base 12 using the fastener 16.

The ferrite plate 23 is provided between the protective cover 11 and thebase 12. The fastener 16 penetrates the ferrite plate 23 to fasten theprotective cover 11 and the base 12. Therefore, the housing 10 is morestrongly fixed to the bobbin 20. Further, movement of the ferrite plate23 in the wound wire direction and the winding axis direction isregulated.

The fastener 16 penetrates through the protrusion 22 c disposed insidethe hole portion 23 a of the ferrite plate 23 to fasten the firstwinding plate 21 and the second winding plate 22. The first windingplate 21 and the second winding plate 22 are more strongly fastened. Theferrite plate 23 does not touch the fastener 16, and is indirectly fixedby the fastener 16. The ferrite plate 23 is sandwiched between and heldby the first winding plate 21 and the second winding plate 22. Ingeneral, the ferrite plate 23 may be fragile. However, according to theabove-described configuration, strength of the ferrite plate 23 isincreased.

The protective cover 11 is supported by the coil portion C through theflange portion 18 a of the cylindrical member 18. The protective cover11 does not touch the first winding plate 21 of the coil portion C, andtouches the flange portion 18 a. Therefore, the first winding plate 21is protected. The gap G is formed between the between the protectivecover 11 and the coil portion C. However, a portion of the protectivecover 11 (specifically, the seat 11 b) protrudes, and the protectivecover 11 is supported by the coil portion C through the protrudingportion. Therefore, the protective cover 11 may be reliably preventedfrom being bent around the fastener.

Since the fastener 16 penetrates through the housing 10, fastening usingthe fastener 16 may be easily performed from the outside of the housing10. Therefore, the fastener 16 may be reliably and easily provided.

A pitch of the conductive wire in the equal portion 35 of the coilportion C is equal to a pitch in another portion. Thus, a variation inmagnetic field distribution generated by the coil portion C may be madeas small as possible when compared to a case in which the fastener 16 isnot provided. The fastener 16 is obliquely disposed with respect to theplane orthogonal to the winding axis direction. Thus, even when thefastener 16 is provided in the equal portion 35, interference in theconductive wire 30 may be easily avoided.

Since the fastener 16 is provided in the first central region A1 of thebobbin 20 in the wound wire direction and the winding axis direction,strength of the housing 10 is increased at a position corresponding tothe first central region A1 of the bobbin 20. When the fastener 16 isnot provided, the housing 10 is relatively easily bent at a positioncorresponding to the second central region A2 of the bobbin 20. Strengthof housing 10 is further improved by the fastener 16.

Even when the fastener 16 is provided in the second central region A2 ofthe housing 10 in the wound wire direction and the winding axisdirection, strength of the housing 10 is increased at a positioncorresponding to the second central region A2 of the housing 10. Whenthe fastener 16 is not provided, the housing 10 is relatively easilybent in the second central region A2. Strength of housing 10 is furtherimproved by the fastener 16.

The coil device 5 has advantageous effect in contrast with the aboverespective conventional art documents. In the above Patent Literature 1,there is no examination of a scheme of attaching the power receptioncoil device to the outside of the vehicle. When the power reception coildevice is installed inside the vehicle, the power reception coil deviceis supported by the chassis. However, it is unclear how to suspend thepower reception coil device when the power reception coil device isinstalled to be exposed to the outside of the chassis of the vehicle. Ingeneral, as a distance between the power transmission coil device andthe power reception coil device decreases, transmitting efficiencyincreases. Thus, there is a great need to attach the power receptioncoil device to the outside of the chassis of the vehicle. In thisregard, according to the coil device 5 of the present embodiment, thebase 12 is fixed to the outside of the chassis. When the protectivecover 11 facing the power transmission coil device 4 is made of anon-magnetic material, for example, resin, a magnetic flux generated bythe coil device 4 is not affected. Therefore, efficient wireless powertransfer is achieved. Further, when a non-magnetic and non-conductingmaterial is used for the protective cover 11, power efficiency ofwireless power transfer may be further increased. When the base 12facing the vehicle body side is made of a non-magnetic and conductivematerial, structural strength of the coil device 5 may be improved whilesuppressing an influence on a magnetic field distribution between thecoil device 4 and the coil device 5. In addition, the non-magnetic andconductive base 12 functions as a magnetic shielding, and thus magneticfluxes heading the coil devices 4 and 5 increase, and power efficiencymay be improved.

In the above Patent Literature 2, an outer circumferential portion ofthe bobbin is attached to the vehicle, and thus a central region is notfixed. For this reason, there is concern that a central region may beeasily bent and broken, thereby causing damage due to external impacteven when the power reception coil device of Patent Literature 1 isattached as in Patent Literature 2. In addition, the power receptioncoil device is subjected to thermal strain due to power reception, orreceives a vibration of the vehicle. The central region, which is notfixed, is easily affected by a force generated in these circumstances.In this regard, according to the coil device 5 of the presentembodiment, strength of the central region of the housing 10 isincreased, and the above-mentioned problem is solved.

The above Patent Literature 3 discloses that a central region of thesubstrate is bolted. However, only the substrate is fixed, and theprotective cover is not fixed. For this reason, a central region of theprotective cover is bent similarly to Patent Literature 2. In addition,Patent Literature 2 mentions a spacer for ensuring strength of theprotective cover. However, when the power reception unit is attachedbackward, and the protective cover is bent, a gap is generated betweenthe spacer and the protective cover. Thus, there is difficulty inensuring strength of the protective cover. In this regard, in the coildevice 5 of the present embodiment, the housing 10 and the bobbin 20 arefastened by the fastener 16, and thus strength of the housing 10 isensured.

Originally, the bolt or the spacer may be provided in the central regionof the power reception unit as in Patent Literature 3 since the coil hasa circular shape in which a space is present in the central region.There is difficulty in employing a scheme of Patent Literature 3 in asolenoid coil as in Patent Literature 1 in which a conductive wire iswound around a central region. In addition, a cross-sectional view ofthe power reception coil device is given in FIG. 7 of Patent Literature1, and conductive wire positions of an upper ferrite housing portion anda lower ferrite housing portion are matched with each other. Thus, thebolt may be vertically inserted so as not to interfere in the conductivewire. However, a pitch of the conductive wire may not be longer than awidth of the bolt. As disclosed in Patent Literature 2 (paragraph 0025),when the conductive wire is sparsely and densely wound, there areproblems of heating due to an eddy current in a dense part and amagnetic flux leakage in a sparse part, and thus the conductive wire ispreferably wound at equal intervals. For this reason, when the pitch ofthe conductive wire is set to be wider than the width of the bolt, thepower reception coil device increases in size as a whole. However, thepower reception coil device is required to be reduced in size due to acharacteristic that the power reception coil device is installed in avehicle in which an installation position is restricted. In addition,the conductive wire needs to be densely wound to improve transmittingefficiency. For this reason, there is difficulty in setting all pitchesof the conductive wire to be wider than the width of the bolt. Further,positions of the conductive wire are provided in a diagonal shape ratherthan being vertically matched in many cases in terms of ensuring aninsulation distance (necessity of separating pieces of the conductivewire as much as possible) (see the surface-side extending portions 31and the rear surface-side extending portions 32 illustrated in FIG. 14).In this case, one of upper and lower pitches of the conductive wire (agap between the surface-side extending portions 31 and 31) includesanother conductive wire position (the rear surface-side extendingportion 32), and thus there is difficulty in inserting a bolt 116 suchthat the conductive wire is not interfered. In this regard, in the coildevice 5 of the present embodiment, the above-mentioned various problemsare overcome.

The present invention is not limited to the above-described embodiment.The present invention includes various modifications. In the aboveembodiment, a description has been given of a mode in which arrangementof the fastener 16 is determined based on the first central region A1 ofthe bobbin 20 or the second central region A2 of the housing 10.However, arrangement of the fastener 16 may be determined based onanother criterion.

For example, as illustrated in FIG. 6A, arrangement of the fastener 16may be determined based on a viewpoint on a magnetic flux. In the bobbin20, regions FS and FS in which a magnetic flux is strong are formed atboth end portions in the winding axis direction. Regions FM and FM inwhich a magnetic flux is moderate are formed at both end portions in thewound wire direction. A magnetic flux is relatively weak in a centralregion FW in the winding axis direction and the wound wire directionexcept for the region FS and the region FM. In some modes, one or aplurality of fasteners 16 may be disposed in the region FM in which themagnetic flux is weak.

A description will be given of a specific range of the region FW inwhich the magnetic flux is weak. The regions FS and FS in which themagnetic flux is strong are regions corresponding to 20% to 40% of awhole length of the coil portion C in the winding axis direction fromboth end portions of the coil portion C. The regions FM and FM in whichthe magnetic flux is moderate are regions corresponding to 20% to 40% ofa whole length of the coil portion C in the wound wire direction fromboth end portions of the coil portion C. Therefore, for example, theregion FW in which the magnetic flux is weak corresponds to a region ina range of 20% to 60% in the middle in the winding axis direction and aregion in a range of 20% to 60% in the middle in the winding axisdirection.

When a determination scheme based on the viewpoint on the magnetic fluxis described from another point of view, the fastener 16 may be providedin a region in which a decrease in power efficiency due to provision ofthe fastener 16 is less than or equal to 0.1%. In this case, aninfluence on power efficiency by the fastener 16 may be made as small aspossible. When the determination scheme based on the viewpoint on themagnetic flux is described from another different point of view, thefastener 16 may be provided in a region in which a magnetic flux densityin the coil portion C is lower than that in another region. In thiscase, an influence on a magnetic flux by the fastener 16 may be made assmall as possible. An average magnetic flux density in a plurality ofregions may be calculated, and the fastener 16 may be provided in aregion in which a magnetic flux density is lower than the average. Thefastener 16 may be provided in a region in which a magnetic flux densityis lowest.

As illustrated in FIG. 6B, arrangement of the fastener 16 may bedetermined based on a viewpoint on strength. In some modes, one or aplurality of fasteners 16 may be provided in a rectangular-shaped regionA3 extending in a short-side direction of the bobbin 20 (that is, thewinding axis direction) in which the intersection point of the firstdiagonal lines L1 and L1 of the bobbin 20 is set as a center.

As illustrated in FIG. 7, one or a plurality of fasteners 16 may beprovided in a region A4 where the region FW in which the magnetic fluxis weak overlaps the rectangular-shaped region A3.

As illustrated in FIG. 8, it is possible to employ a mode in which afastener is divided into two parts corresponding to a fastener 16A onthe protective cover 11 side and a fastener 16A on the base 12 side. Therespective fasteners 16A and 16A are obliquely disposed with respect tothe plane orthogonal to the winding axis direction. In this case, thetwo fasteners 16A and 16A are provided from the outside of the housing10. The fastener 16A on the protective cover 11 side penetrates throughthe protective cover 11, and does not penetrate through the ferriteplate 23. The fastener 16A on the base 12 side penetrates through thebase 12, and does not penetrate through the ferrite plate 23. In otherwords, a distal end of the fastener 16A terminates inside the firstwinding plate 21 or the second winding plate 22. A seal member isprovided between the fastener 16A on the protective cover 11 side andthe protective cover 11. A seal member is provided between the fastener16A on the base 12 side and the base 12.

As illustrated in FIG. 9, it is possible to employ a mode in which afastener is divided into two parts corresponding to a fastener 16B onthe protective cover 11 side and a fastener 16B on the base 12 side. Therespective fasteners 16B and 16B are obliquely disposed with respect tothe plane orthogonal to the winding axis direction. In this case, thetwo fasteners 16B and 16B are provided from the inside of the bobbin 20(that is, the ferrite plate 23 side of the first winding plate 21 andthe ferrite plate 23 side of the second winding plate 22). The fastener16B on the protective cover 11 side does not penetrate through theprotective cover 11 and the ferrite plate 23. The fastener 16B on thebase 12 side does not penetrate through the base 12 and the ferriteplate 23. In other words, a base end of the fastener 16B does notprotrude from a surface of the first winding plate 21 or the secondwinding plate 22 on the ferrite plate 23 side. A distal end of thefastener 16B on the protective cover 11 side terminates inside theprotective cover 11. A distal end of the fastener 16B on the base 12side terminates inside the base 12. A seal member is not needed betweenthe fastener 16B on the protective cover 11 side and the protectivecover 11. A seal member is not needed between the fastener 16B on thebase 12 side and the base 12.

As illustrated in FIG. 10, it is possible to employ a mode in which twofasteners 16C and 16C are provided on the protective cover 11 side. Therespective fasteners 16C and 16C are obliquely disposed with respect tothe plane orthogonal to the winding axis direction. The fasteners 16Cand 16C penetrate through the protective cover 11 and the ferrite plate23. Distal ends of the fasteners 16C and 16C terminate inside the base12. Seal members are provided between the fasteners 16C and 16C and theprotective cover 11.

As illustrated in FIG. 11, it is possible to employ a mode in which aplurality of miniaturized screw members is used. FIG. 11 illustrates acase in which four fasteners 16D are provided. Some (or all) of theplurality of fasteners 16D are obliquely disposed with respect to theplane orthogonal to the winding axis direction. A thickness (diameter)of each of the fasteners 16D may be appropriately changed. For example,one medium-sized fastener 16D is used on the protective cover 11 side tofasten the protective cover 11 and the first winding plate 21. Thesecond winding plate 22 and the ferrite plate 23 are fastened by twosmall-sized fasteners 16D and 16D on the base 12 side. Further, the base12 and the second winding plate 22 are fastened by one small-sizedfastener 16D. A seal member is provided between the fastener 16D and theprotective cover 11 or the base 12 only when the fastener 16D penetratesthrough the protective cover 11 or the base 12. The “middle-sizedfastener” and the “small-sized fastener” correspond to thicknesses(diameters) when the one fastener 16 illustrated in FIG. 3A and FIG. 3Bis set as a criterion. When a plurality of middle-sized or small-sizedfasteners is used, an influence on a magnetic field distribution may bereduced.

As illustrated in FIG. 12, a key structure may be provided inside theprotective cover 11 and the base 12. That is, a fastener 16E includes afirst combined member 11 e integrally provided with a protective cover11E to protrude toward a base 12E, and a second combined member 12 eintegrally provided with the base 12E to protrude toward the protectivecover 11E. At least one of the first combined member 11 e and the secondcombined member 12 e is disposed inside a coil portion CE. In otherwords, at least one of the first combined member 11 e and the secondcombined member 12 e intersects with (enters) the coil portion CE. Thefirst combined member 11 e and the second combined member 12 e arecombined together. The first combined member 11 e and the secondcombined member 12 e are obliquely disposed with respect to the planeorthogonal to the winding axis direction while being combined with eachother. More specifically, the fastener 16E is configured such that adistal end of the first combined member 11 e fits into a depression of adistal end of the second combined member 12 e. As the protective cover11E is further pressed against the base 12E, fastening strength betweenthe first combined member 11 e and the second combined member 12 eincreases. In this case, the fastener 16E is integrally provided with ahousing 10E, and does not penetrate through the housing 10E, and thus aseal around the fastener 16E is not needed.

As illustrated in FIG. 13A, two (a plurality of) fasteners 16F may bearranged along the winding axis direction. In this case, the fasteners16F and 16F may be provided in point symmetry about the intersectionpoint of the first diagonal lines L1 and L1, that is, the central pointof the bobbin 20 (see FIG. 5). In this way, loads applied to both thefasteners 16F and 16F may be easily balanced, and thus strength of theprotective cover may be easily increased.

As illustrated in FIG. 13B, two (a plurality of) fasteners 16G may bearranged along the wound wire direction. In this case, the fasteners 16Gand 16G may be provided in point symmetry about the intersection pointof the first diagonal lines L1 and L1, that is, the central point of thebobbin 20 (see FIG. 5).

If one or a plurality of fasteners is provided as described above, asize of the fastener may be determined such that a surface area of asurface through which magnetic fluxes of the fastener pass is the sameas a surface area obtained when one fastener 16 is provided. When asurface area of a surface through which magnetic fluxes pass isprevented from increasing, a demerit due to a plurality of fasteners isexcluded. For example, the fasteners 16A to 16G may be disposed along aplane orthogonal to the wound wire direction. The plane orthogonal tothe wound wire direction refers to a virtual plane that extends in thewinding axis direction and the vertical direction (that is, the platethickness direction of the first winding plate 21 and the second windingplate 22). In this case, with regard to the fasteners 16A to 16G, it ispossible to minimize a surface area of a surface through which magneticfluxes pass.

The present invention is not limited to a case in which a gap betweenthe surface-side extending portions 31 and 31 is uniform in all portionson the first winding plate 21, and the gap between the surface-sideextending portions 31 and 31 may be non-uniform in one portion. In thiscase, a pitch of some of the plurality of groove portions 2 lb may bedifferent from a pitch of other portions. The present invention is notlimited to a case in which a gap between the rear surface-side extendingportions 32 and 32 is uniform in all portions on the second windingplate 22, and the gap between the rear surface-side extending portions32 and 32 may be non-uniform in one portion. In this case, a pitch ofsome of the plurality of groove portions 22 b may be different from apitch of other portions.

A description has been given of a case in which the groove portions 21 band the groove portions 22 b are formed on the first winding plate 21and the second winding plate 22. However, the present invention is notlimited to this case. The groove portions may not be formed on thewinding plates, and the conductive wire 30 may extend on a surface of aflat winding plate. The distal end portion 17 c of the fastener 16 maypenetrate through the base 12. That is, the distal end portion 17 c ofthe fastener 16 may protrude to the EV side. For example, the distal endportion 17 c penetrating through the base 12 is screwed to the vehiclebody, and the coil device 5 is more strongly installed in the vehicle.Any member capable of fastening the bobbin and the housing may be usedas the fastener, and a screw, a rivet, etc. may be used.

The present invention is not limited to a case in which the bobbin 20 isdisposed on the base 12 such that the first central region A1 and thesecond central region A2 do not fully overlap each other (see FIG. 5).For example, the bobbin 20 may be disposed on the base 12 such that acenter of the bobbin 20 overlaps a center of the base 12.

The above embodiment gives an example in which the litz wire is used asthe conductive wire 30. However, the present invention is not limitedthereto. A conductive wire other than the litz wire may be used as longas the conductive wire functions as a coil device for wireless powertransfer. For example, a type, a figure, a form, a material, aconfiguration, a shape, and a dimension of the conductive wire 30 arearbitrarily selected.

In the above embodiment, a description has been given on a case in whichthe present disclosure is applied to the coil device 5. However, thepresent invention is not limited thereto. The present disclosure may beapplied to the power transmission coil device 4. In addition, in theabove embodiment, a description has been given on a case in which thecoil device of the present disclosure is applied to the wireless powertransfer system. However, a system to which the coil device is appliedis not restricted to the wireless power transfer system. For example,the coil device of the present disclosure may be applied to an inductionheating system or an eddy current flaw detection system.

INDUSTRIAL APPLICABILITY

According to some embodiments of the present disclosure, strength of ahousing may be increased in a coil device of solenoid type.

1. A coil device of solenoid type comprising: a coil portion having abobbin and a conductive wire wound around the bobbin; a housing foraccommodating the coil portion; and at least one fastener for fasteningthe bobbin and the housing, wherein the conductive wire includes aplurality of extending portions extending along a wound wire directionon the bobbin and having gaps in a winding axis direction, and thefastener is provided between the plurality of extending portions, and isobliquely disposed with respect to a plane orthogonal to the windingaxis direction.
 2. The coil device according to claim 1, wherein thecoil portion further includes a magnetic member disposed inside thebobbin.
 3. The coil device according to claim 2, wherein the housingincludes a first housing member facing a first surface of the coilportion having a flat plate shape, and a second housing member fixed tothe first housing member to face a second surface on an opposite sidefrom the first surface.
 4. The coil device according to claim 3, whereinthe bobbin includes a first winding plate disposed between the firsthousing member and the magnetic member, and a second winding platedisposed between the second housing member and the magnetic member, andthe fastener penetrates through the magnetic member and fastens thefirst winding plate and the second winding plate.
 5. The coil deviceaccording to claim 4, wherein a hole portion is provided in the magneticmember, one of the first winding plate and the second winding plateincludes a protrusion protruding to an inside of the hole portion, andthe fastener penetrates through the protrusion to fasten the firstwinding plate and the second winding plate.
 6. The coil device accordingto claim 4, wherein the fastener includes a flange portion contactingthe first winding plate from a side of the first housing member, and thefirst housing member is supported by the coil portion through the flangeportion.
 7. The coil device according to claim 1, wherein the fastenerpenetrates through the housing.
 8. The coil device according to claim 3,wherein the fastener includes a first combined member integrallyprovided in the first housing member to protrude toward the secondhousing member, and a second combined member integrally provided in thesecond housing member to protrude toward the first housing member, andat least one of the first combined member and the second combined memberis disposed inside the coil portion, and the first combined member andthe second combined member are combined together.
 9. The coil deviceaccording to claim 1, wherein the coil portion includes an equal portionin which a gap between extending portions adjacent to each other in thewinding axis direction is equal to a gap between other extendingportions, and the fastener is provided in the equal portion.
 10. Thecoil device according to claim 1, wherein the fastener is provided in acentral region of the bobbin in the wound wire direction and the windingaxis direction.
 11. The coil device according to claim 1, wherein thefastener is provided in a central region of the housing in the woundwire direction and the winding axis direction.
 12. The coil deviceaccording to claim 1, wherein the fastener is provided in a region inwhich a decrease in power efficiency due to provision of the fastener isless than or equal to 0.1%.
 13. The coil device according to claim 1,wherein the fastener is provided in a region in which a magnetic fluxdensity in the coil portion is lower than a magnetic flux density inanother region.
 14. The coil device according to claim 1, wherein the atleast one fastener comprises a plurality of fasteners, and the pluralityof fasteners are arranged along the winding axis direction.
 15. The coildevice according to claim 1, wherein the at least one fastener comprisesa plurality of fasteners, and the plurality of fasteners are arrangedalong the wound wire direction.